The present invention relates to drip irrigation emitters, and particularly to regulated emitters for supplying irrigation water at a relatively constant rate irrespective of fluctuations in the water supply pressure.
A number of regulated drip irrigation emitters have been described in the patent literature. One type, called an "off-line" emitter, is attachable as an off-line branch to a water supply pipe; examples of such emitters are described in U.S. Pat. Nos. 4,209,133, 4,384,680, 4,718,608, and 4,307,841. Another type, called an "in-line" emitter, is fixed to the inner face of the water supply pipe so as to be connected in-line with respect to the water flowing therethrough; an example of such a regulated emitter is described in U.S. Pat. No. 4,687,143).